Field changeable rendering system for a computing device

ABSTRACT

One embodiment of a field changeable rendering system includes an output device interfaced to a motherboard, a fixed rendering device mounted to the motherboard for generating information to be output on said output device, a connector for attaching a field-changeable rendering card to the motherboard, said field-changeable rendering card capable of housing a discrete rendering device for generating information to be output on said output device and detection circuitry for detecting that a field-changeable rendering card housing a discrete rendering device is coupled to said connector and causing information from said field-changeable rendering card housing a discrete rendering device to be output on said output device. One advantage of the disclosed edge connector is that it is compatible with a plurality of graphics cards and systems, thereby enabling a computing device user to upgrade the existing device&#39;s graphics system. Thus, the user is not forced to purchase an entirely new computing device in order to take advantage of graphics innovations. A further advantage of the disclosed edge connector is that it enables upgrades to low voltage differential signaling (LVDS) features, without the need for additional costly devices capable of operating at LVDS data rates.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to computer hardware and relates moreparticularly to a field changeable rendering system for a computingdevice.

2. Description of the Background Art

Contemporary computing devices typically incorporate a graphics cardthat enables a computing device to rapidly process graphics related datafor graphics intensive applications, such as gaming applications. Agraphics card generally comprises a printed circuit board (PCB) uponwhich a plurality of circuit components (such as memory chips and thelike) and a graphics processing unit (GPU) are mounted. In “closedplatform” computing devices such as laptop computers, cellulartelephones and personal digital assistants (PDAs) (i.e., devices thatuse processors and are not easily changed by a user), the graphics cardis mounted directly and permanently to the motherboard of the computingdevice.

One drawback to mounting the graphics card directly to the motherboardis that this fixed configuration impedes a user's ability to upgrade thecomputing device's graphics system. Specifically, in order to takeadvantage of an improved graphics system, the user typically mustpurchase an entirely new computing device, which is much more costlythan a simple replacement of the graphics system in the existingcomputing device. The same is true for upgrading othermotherboard-mounted rendering devices, such as audio chips.

A second drawback is that the pace of graphics innovations that can beconveniently delivered to computing device users is hindered, becausethe implementation of on-board devices is typically limited by a designcycle of approximately nine to twelve months.

Thus, there is a need in the art for a field changeable rendering systemfor a computing device.

SUMMARY OF THE INVENTION

One embodiment of a field changeable rendering system includes an outputdevice interfaced to a motherboard, a fixed rendering device mounted tothe motherboard for generating information to be output on said outputdevice, a connector for attaching a field-changeable rendering card tothe motherboard, said field-changeable rendering card capable of housinga discrete rendering device for generating information to be output onsaid output device and detection circuitry for detecting that afield-changeable rendering card housing a discrete rendering device iscoupled to said connector and causing information from saidfield-changeable rendering card housing a discrete rendering device tobe output on said output device.

One advantage of the disclosed rendering system is that it is compatiblewith a plurality of graphics cards and systems, thereby enabling acomputing device user to upgrade the existing device's graphics system.Thus, the user is not forced to purchase an entirely new computingdevice in order to take advantage of graphics innovations. Thisadvantage is particularly significant for users of portable computingdevices, such as laptop computers, cellular telephones and PDAs, orother devices traditionally having fixed graphics functionality such asvideo game consoles.

A further advantage of the disclosed rendering system is that it enablesupgrades to low voltage differential signaling (LVDS) features, withoutthe need for an additional (and typically costly) device that is capableof operating at LVDS data rates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view illustrating a field changeable rendering system,wherein the rendering system is a graphics card, according to oneembodiment of the present invention.

FIG. 2 is a top plan view illustrating a graphics card for use in fieldchangeable rendering system of FIG. 1, according to one embodiment ofthe present invention;

FIGS. 3A-B are tables illustrating one embodiment of a pinout for theedge connector illustrated in FIG. 2;

FIGS. 4A-C are tables containing contact pin descriptions for eachsignal type identified in FIGS. 3A-B;

FIG. 5 is a table summarizing the power that must be supplied through anedge connector from a motherboard to a graphics card, according to oneembodiment of the present invention;

FIG. 6A is a schematic diagram illustrating a configurable graphicssystem according to one embodiment of the present invention;

FIG. 6B is a schematic diagram illustrating graphics system according toanother embodiment of the present invention;

FIG. 7A is a schematic diagram illustrating a user-upgradeable graphicssystem, according to one embodiment of the present invention; and

FIG. 7B is a schematic diagram illustrating a user-upgradeable graphicssystem, according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a side view illustrating a field changeable rendering system100, according to one embodiment of the present invention. Renderingsystem 100 is a graphics system, and is adaptable for use with any typeof computing device, including, without limitation, a desktop computer,server, laptop computer, palm-sized computer, personal digitalassistant, tablet computer, game console, cellular telephone,computer-based simulator and the like. As will be explained in furtherdetail below in conjunction with FIGS. 6A-7B, graphics system 100 isconfigured to ensure compatibility with a plurality of field changeablegraphics cards.

Generally, system 100 is configured to interface with a computing devicemotherboard 102 in lieu of a conventional graphics card and includes,without limitation, a graphics card 104 and an interface assembly 150.Graphics card 104 includes a GPU and a plurality of circuit componentsincluding memory (not shown) mounted to a first face 101, typicallyfacing away from motherboard 102. Graphics card 104 further comprises acard connector 106 positioned along an edge 105 of graphics card 104 andadapted to engage interface assembly 150. Several embodiments of fieldchangeable graphics cards suitable for use in rendering system 100 aredescribed in co-pending, commonly assigned U.S. patent application Ser.No. ______, filed ______ by Bisson et al. (Attorney Docket No.NVDA/P001196), which is herein incorporated by reference.

As also described in further detail below in conjunction with FIGS. 2-5,rendering system 100 is configured to interface with motherboard 102without being directly mounted to motherboard 102. This is enabled byinterface assembly 150, which includes, without limitation, one or moresupports 108 and an edge connector 114. Supports 108 are mounted tomotherboard 102 and extend upward therefrom to engage graphics card 104.Supports 108 are adapted to stably maintain graphics card 104 in aspaced-apart orientation relative to motherboard 102. In one embodiment,supports 108 are sized to maintain a distance d between graphics card104 and motherboard 102 that is approximately 4 mm.

Also as described in conjunction with FIG. 2, edge connector 114 ismounted to motherboard 102 and includes a lengthwise channel 116 havinga plurality of contacts disposed on upper and lower surfaces 118, 120.The contacts are adapted for engaging card connector 106 on graphicscard 104, for routing external and internal interfaces from graphicscard 104 to motherboard 102.

FIG. 2 is an isometric view illustrating one embodiment of an edgeconnector 200 according to the present invention. Edge connector 200 isadapted to route all internal and external interfaces from a graphicscard (e.g., graphics card 104 of FIG. 1) to a motherboard of a computingdevice. Edge connector 200 comprises an elongated body 202 having alongitudinal slot 204 formed therein. Longitudinal slot 204 is sized toreceive an edge of a graphics card connector (e.g., card connector 106).In one embodiment, longitudinal slot 204 is sized to accommodate cardthicknesses of up to 1.2 mm. Contact pins (not shown) disposed on topand bottom surfaces 206, 208 of longitudinal slot 204 are adapted tointerface with contacts on a card connector.

FIGS. 3A-B are tables illustrating one embodiment of a pinout for edgeconnector 200. Each contact pin on edge connector 200 is associated withan individual signal (e.g., power input, ground and the like). In theembodiment illustrated, edge connector 200 utilizes a 230-pin card-edgeconnection system, wherein contact pins on edge connector 200 are ratedfor 0.5 A steady state current. FIGS. 4A-C are tables containing contactpin descriptions for each signal type identified in FIGS. 3A-B.Input/output classifications in FIGS. 4A-C are relative to a GPU mountedon the graphics card. References to “MXM module” indicate a graphicscard according to the present invention.

FIG. 5 is a table summarizing the power that must be supplied by themotherboard to a graphics card, i.e., through edge connector 200,according to one embodiment of the present invention. If themotherboard's power supply equals or exceeds the power requirementssummarized in FIG. 5, a graphics card interfaced to an edge connectoraccording to the present invention (e.g., edge connector 200) will runat full speed. However, the interface will also allow a graphics card todetect power supply limitations of the motherboard and to automaticallythrottle its clocks to stay within the limits of the available power.

In addition to the power requirements summarized in FIG. 5, amotherboard must meet a plurality of additional system requirements inorder to effectively interface to a graphics system of the presentinvention. For example, in one embodiment, the motherboard is requiredto place a serial ROM that connects to the DDCC_DAT and DDCC_CLK signals(e.g., connector pins 220 and 222 in FIG. 3B). In addition, themotherboard must provide back drive isolation and level shifting, forall DDC lines, VGA_HSYNC and VGA_VSYNC signals (e.g., connector pins 151and 153). Furthermore, the motherboard must provide power to thecomputing device LVDS panel, and must route all RGB signals and TV_outsignals with 37.5 Ohms impedance. In one embodiment, the motherboard isalso required to have output filters on all VGA output lines and on allTV output lines, the filters being positioned as closely as possible tothe connector pins. Input filters are required on the DVI_B_HPD andDVI_A_HPD lines (e.g., connector pins 191 and 217), and the graphicscard will provide level shifting and clamping for the DVI_B_HPD andDVI_A_HPD signals.

In one embodiment, an edge connector according to the present invention(e.g., edge connector 200) is adapted to detect a graphics mode of acomputing device, and to cause display interfaces to be routed from agraphics card to the motherboard accordingly. Specifically, the PRSNT#1connector pin on the edge connector (e.g., pin 134 in the pinout ofFIGS. 3A-B) is adapted to detect if a graphics upgrade, such as any oneof the graphics cards disclosed in U.S. patent application Ser. No.______, has been implemented in the computing device. In one embodiment,a voltage detected by the PRSNT #1 connector pin indicates the presenceof a graphics upgrade. For example, a high voltage detected by thePRSNT#1 connector pin indicates that a “dummy” or “loop-through” card(e.g., a card with no graphics processing unit) is interfaced to theedge connector, as explained in further detail in conjunction with FIGS.6A and 7A below. Alternatively, a low voltage detected by the PRSNT# 1connector pin indicates that a graphics upgrade such as a graphics cardis interfaced to the edge connector, as explained in further detail inconjunction with FIGS. 6B and 7B below.

FIG. 6A is a schematic diagram illustrating a configurable graphicssystem 600, according to one embodiment of the present invention. Theoutput topology illustrated in FIG. 6A depicts a manufacturing-endgraphics configuration (i.e., graphics system 600 is incorporated duringassembly of the computing device). Graphics system 600 comprises a fixed(e.g., mounted to the motherboard) rendering device such as a standardintegrated graphics processor (IGP) 612 (driven in one embodiment by aNorthbridge chip set, not shown), a loop-through card 650, and aplurality of output display panels 604-610 for video graphics array(VGA), television (TV), low voltage differential signaling (LVDS) anddigital video interface (DVI) signals, all interfaced to a motherboard.The display output signals are generated by IGP 612 in conjunction withloop-through card 650, as described further below.

Loop-through card 650 may be implemented in graphics system 600 in placeof a conventional LVDS capable device. As described above, the PRSNT #1connector pin on the edge connector detects a high voltage and sends acorresponding signal to the Northbridge chip set indicating the presenceof loop-through card 650. Consequently, the Northbridge outputs LVDSsignals to the edge connector, in one embodiment connecting the signalsto the IGP_LVDS connector pins. The passive loop-through card 650completes the circuit paths between the output signals and the LVDSpanel input signals. Thus, the edge connector, in conjunction withloop-through card 650, enables a computing device user to implement LVDSfeatures without the need to implement complex (and costly) traditionalLVDS-capable devices.

In one embodiment, the graphics system 600 further supports DVI. In thisembodiment, DVI signals are output to the DVI_A connector pins (e.g.,connector pins 219, 221, 225, 227, 231, 233, 237 and 239 in FIG. 3B) onthe edge connector and routed to loop-through card 650, which furthercomprises a discrete rendering device such as a transmission minimizeddifferential signaling (TMDS) transmitter for driving TMDS outputs onreceived signals. TV and VGA signals are output from the Northbridgechip set to IGP 612 in accordance with standard IGP operation.

In one embodiment, graphics system 600 further comprises a plurality ofstuffing resistors 614 a and 614 b (shown in phantom) adapted forcompleting the circuits from IGP 612 and from loop-through card 650 tooutput display panels 604-610. During assembly of a computing system, amanufacturer may configure graphics system 600 to operate in the modedescribed (e.g., incorporating loop-through card 650) by closing thecircuit paths through resistors 614 a and leaving the circuit pathsthrough resistors 614 b open.

Alternatively, as illustrated in FIG. 6B, a manufacturer may close thecircuit paths through resistors 614 b and leave the circuit pathsthrough resistors 614 a open, in order to implement an active graphicscard. In this embodiment, graphics system 600 comprises a graphics card660 in place of loop-through card 650. Graphics card 660 may beconfigured in a manner similar to any one of the graphics cardsdescribed in U.S. Pat. No. ______, and includes a discrete renderingdevice such as a graphics processing unit. Graphics card 660 generatessubstantially all display output signals, as described further below.

As described above, the PRSNT #1 connector pin on the edge connectordetects a low voltage and sends a corresponding signal to theNorthbridge chip set indicating the presence of graphics card 660.Consequently, the Northbridge outputs a peripheral component interface(PCI) Express signal to the edge connector, which routes the signal tographics card 660. VGA, TV, LVDS and DVI signals are subsequentlygenerated by graphics card 660. As described above, stuffing resistors614 b complete the circuits from graphics card 660 to display panels604-610.

FIG. 7A is a schematic diagram illustrating a graphics system 700according to one embodiment of the present invention. The outputtopology illustrated in FIG. 7A depicts a user-upgradeableconfiguration. That is, a user may upgrade graphics system 700 ondemand, by simply exchanging one field-exchangeable graphics card foranother. Graphics system 700 is substantially similar to graphics system600 illustrated in FIG. 6A and comprises an IGP 712, a loop-through card702, and a plurality of display panels 704-710 for VGA, TV, LVDS and DVIsignals. The display output signals are generated by IGP 712 inconjunction with loop-through card 702, as described further below.

LVDS and DVI signals are output by the Northbridge to the edge connectoras described above in conjunction with FIG. 6A. The passive loop-throughcard 702 completes the circuit paths between the output signals and theLVDS and DVI panel input signals. TV and VGA signals are output from theNorthbridge chip set to IGP 712 in accordance with standard IGPoperation. In one embodiment, graphics system 700 further comprises aplurality of muxes 714 adapted for receiving and transmittingIGP-initiated signals (e.g., for VGA and TV signals). During assembly ofa computing system, a manufacturer may configure graphics system 700 tooperate in the mode illustrated in FIG. 7A (e.g., incorporatingloop-through card 702) as a default.

FIG. 7B is a schematic diagram illustrating graphics system 700 in anupgraded mode. Graphics system 700 is substantially similar to graphicssystem 600 illustrated in FIG. 6B and comprises an IGP 702, a pluralityof display panels 704-710 for VGA, TV, LVDS and DVI signals and anactive graphics card 760 in place of loop-through card 702.

When the presence of graphics card 760 is detected, the Northbridgesends a PCI Express signal through the edge connector and to graphicscard 760. Muxes 714 are configured to automatically reconfigure toconnect VGA and TV circuit paths to graphics card 760.

An edge connector according to the present invention may thus beconfigured to enable a computing device user to upgrade an existingdevice's graphics system with minimal expense. Because the edgeconnector is adapted to work with a plurality of field-changeablegraphics cards, the user is not forced to purchase an entirely newcomputing device in order to take advantage of graphics innovations.This advantage is particularly significant for users of portablecomputing devices, such as laptop computers and PDAs, in which graphicssystems are frequently difficult or impossible to alter.

A further advantage of the disclosed edge connector is that it enablesupgrades to LVDS features. Typical devices capable of operating at LVDSdata rates tend to be rather costly. However, by configuring the edgeconnector of the present invention to enable LVDS signals to “loopthrough” a passive card, the versatility of the graphics system isenhanced with minimal cost to the user.

Moreover, though the present invention has been described in terms ofgraphics cards, those skilled in the art will appreciate that theinvention may be adapted for use with other devices that are typicallyhardwired to a motherboard, such as audio chips and the like.

Thus, the present invention represents a significant advancement in thefield of computing device graphics systems. An edge connector isprovided that enables a plurality of field-changeable graphics systemsto interface to a single computing device motherboard. The edgeconnector thus maximizes the graphics options that may be implemented inan existing computing device, allowing computing device users greaterability to take advantage of graphics innovations.

Furthermore, the present invention grants more flexibility to computingdevice manufacturers, since it removes the approximately nine to twelvemonth design cycle for on-board implementations. The present inventionalso enables the build-to-order, stock-to-order and field repair of anyof the systems disclosed, which is a significant advancement for aglobal economy having needs for just-in-time manufacturing and inventorymanagement.

Those skilled in the art will appreciate that although the presentinvention has been described in the context of closed platform computingdevices such as laptop computers, cellular telephones and PDAs, thepresent invention may be adapted for use with any device that uses aprocessor and is not easily changed by a user, such as automotivenavigation systems, entertainment systems, all-in-one personalcomputers, printers and the like. Moreover, although the presentinvention has been described in the context of standardized, fieldchangeable graphics cards, the present invention may be deployed inother form factors such as credit card polymer substrates with embeddedchips, and postage stamp-sized, self-contained devices, among others.

Although the invention has been described above with reference tospecific embodiments, persons skilled in the art will understand thatvarious modifications and changes may be made thereto without departingfrom the broader spirit and scope of the invention as set forth in theappended claims. The foregoing description and drawings are,accordingly, to be regarded in an illustrative rather than a restrictivesense.

1. Apparatus comprising: an output device interfaced to a motherboard; afixed rendering device mounted to the motherboard for generatinginformation to be output on said output device; a connector forattaching a field-changeable rendering card to the motherboard, saidfield-changeable rendering card capable of housing a discrete renderingdevice for generating information to be output on said output device;and detection circuitry for detecting that a field-changeable renderingcard housing a discrete rendering device is coupled to said connectorand causing information from said field-changeable rendering cardhousing a discrete rendering device to be output on said output device.2. The apparatus of claim 1, wherein said fixed rendering device is anintegrated graphics processor and said discrete rendering device is adiscrete graphics processing unit.
 3. The apparatus of claim 2, whereinsaid graphics processing unit is adapted to receive a PCI express signalfrom said integrated graphics processor in order to generate a pluralityof signals for display on said output device.
 4. The apparatus of claim3 wherein said graphics processing unit is adapted to generate lowvoltage differential signaling (LVDS), digital video interface (DVI),television (TV) and video graphics array (VGA) signals.
 5. The apparatusof claim 1 wherein said field-changeable rendering card does not house adiscrete rendering device and acts as a passive loop-through card. 6.The apparatus of claim 1, wherein the discrete rendering device is atransmission minimized differential signaling (TMDS) transmitter, andthe field-changeable rendering card is a passive loop-through card. 7.The apparatus of claim 5, wherein said passive loop-through cardcompletes circuit paths for signals output from said fixed renderingdevice to said output device.
 8. The apparatus of claim 7, wherein saidoutput device is a low voltage differential signaling (LVDS) displaypanel.
 9. The apparatus of claim 7, wherein said output device is adigital video interface (DVI) display panel.
 10. The apparatus of claim1, wherein said field-changeable rendering card is an audio chip.